My prior U.S. Pat. No. 4,153,391 discloses a diaphragm pump which is driven by a wobble plate. The wobble plate is mounted for nutating motion by a ball which supports the wobble plate against radial loads. The wobble plate is driven by an input assembly which includes two needle bearings which accommodate the axial loads.
This pump has served very satisfactorily, particularly when used for intermittent duty, such as a water pump for a recreational vehicle. However, for applications where continuous duty is required, the grease for the needle bearings may be thrown out of the needle bearings, and when this occurs, the needle bearings tend to overheat and rust. Ball bearings can be used to drive the wobble plate of a diaphragm pump as shown, for example, by Zubaty U.S. Pat. No. 2,991,723. However, this patented construction employs a relatively heavy wobble plate on one of the ball bearings and a sliding shoe for driving the diaphragm in only one direction. A spring must be located in the pumping chamber, and hence in the fluid being pumped, for driving the diaphragm in the other direction.